With respect to your first question, I'd suggest going for the PhD from the American university. I went to an Ivy League university as an undergraduate, and I've found the network to be extremely valuable. There are networking events in virtually every city for my university, and it's been a great avenue for establishing professional contacts and friendships. In contrast, my brother had great marks but decided to attend a small liberal arts school. The education he received was very good, but there are no alumni mailing lists where he can post his resume or find a reputable roommate.

The famous Peopleware (by Demarco and Lister) has a chapter on this. It brings up a lot of good considerations. The gist of it is that they recommend asking the developers. That's a great place to start, but I've found that a lot of the developers I've worked with are either too young to have much of an opinion about this or too old to think of any solution other than the solutions they've seen in the past. Whenever I've done this in the past (for groups of 2 to 20 people, most of whom were usually developers), I've tried to give everybody his or her own desk but keep people's backs to the wall. I've found that, if nobody can sneak up on you or see your monitor, your working space feels more private. That sense of privacy helps folks concentrate a bit better. Also, if everybody's back is against the wall, it means that everybody's facing the middle of the room, which helps a bit with impromptu discussions. The downside of the backs-to-walls approach is that there's a lot less open space. You probably need about 100 square feet per developer to make it work well.